Miles per hour to kilometers per hour converter

Convert miles per hour to kilometers per hour (mph to km/h) with the exact factor, a conversion chart and worked steps.

Drafted with AI writing toolsUpdated Checked examples: 3

mph
Try
Kilometers per hour
km/h
Kilometers per hour: 96.56064 km/h
Significant figures: 12; Nearest, ties away from zero
Conversion
60 mph = 96.56064 km/h
1 km/h in miles per hour
0.6213711922mph

60 mph is about 96.56064 km/h. In the other direction, 1 km/h ≈ 0.62137119 mph.

Miles per hour to kilometers per hour

05010015020406080100mphkm/h60 → 96.5606
Mph to km/h chart Rows: 13
Miles per hourKilometers per hour
1016.0934
2032.1869
2540.2336
3048.2803
4064.3738
5080.4672
5588.5139
6096.5606
65104.6074
70112.6541
75120.7008
80128.7475
100160.9344
How it's calculated S
  1. Conversion factor

    1 mph=1.609344 km/h1\ \text{mph} = 1.609344\ \text{km/h}

    Exact by definition.

  2. Multiply

    60×1.609344=96.56064 km/h60 \times 1.609344 = 96.56064\ \text{km/h}

About the miles per hour to kilometers per hour converter

To convert miles per hour to kilometers per hour, multiply by 1.609344; to convert back, multiply by 0.6213711922. For example, 60 mph is about 96.56064 km/h. Displayed factors and results may be rounded.

A speed in miles per hour may come from a vehicle display or a road sign. Converting the displayed speed is useful when comparing it with a metric scale. It does not change the posted limit or account for speedometer error and changing road conditions.

mile per hour: 1 mph = 0.44704 m/s. These values are exact.

Both units are defined exactly. Calculations use 50 significant digits and round only for display.

How to convert mph to km/h

Multiply miles per hour by 1.609344, the number of kilometers in a mile: km/h = mph × 1.609344. So 60 mph = 96.56 km/h and 70 mph = 112.65 km/h. The factor is exact and works for any speed in mph, from road signs to wind and pitching speeds.

Multiply by 1.6 for a quick answer

Multiplying by 1.6, which is the same as adding 60%, lands within 0.6%. For 60 mph, 60 × 1.6 = 96 km/h, which is 0.56064 km/h short of the exact 96.56064. At 70 mph the shortcut gives 112 km/h, 0.65 km/h short.

Why the factor is 1.609344

The international mile is 5,280 feet, and a foot is exactly 0.3048 m, so a mile is 1,609.344 m, or 1.609344 km (NIST Handbook 44, Appendix C). The hour is the same in both units, so speed converts by the distance ratio alone.

mph to km/h chart

Miles per hourKilometers per hour
2032.18688
3048.28032
4064.37376
5588.51392
6096.56064
70112.65408

Every value is exact. The metric unit is also written kph or kmh.

UK and US speed limits in km/h

UK road signs are in mph. A 30 mph sign means 48.28032 km/h, and the 70 mph motorway limit is 112.65 km/h. On a US highway posted at 65 mph, the limit is 104.61 km/h.

Running, baseball and physics speeds

  • Running: 6 mph on a treadmill is 9.66 km/h, a 10:00 mile or about 6:13 per kilometer. The running pace calculator converts paces.
  • Baseball: a 100 mph fastball is 160.93 km/h.
  • Physics: 1 mph is exactly 0.44704 m/s, so 60 mph is 26.8224 m/s.

Common mistakes

  • Dividing instead of multiplying. 60 ÷ 1.609344 = 37.28, which is 60 km/h expressed in mph. A kilometer is shorter than a mile, so the km/h number is always the larger one.
  • Confusing speed with distance. Miles and mph share the 1.609344 factor, but a speed becomes a distance only after multiplying by time: 60 mph for half an hour covers 30 miles, or 48.28032 km. Use miles to km for distances.

For the reverse, use km/h to mph. The speed converter also handles knots, m/s and ft/s.

Worked examples

60 mph to km/h

Miles per hour (mph)
60 mph
Kilometers per hour
96.56064 km/h

Checked against: Exact-fraction computation from the legal unit definitions

40 mph to km/h

Miles per hour (mph)
40 mph
Kilometers per hour
64.37376 km/h

Checked against: Exact-fraction computation from the legal unit definitions

80 mph to km/h

Miles per hour (mph)
80 mph
Kilometers per hour
128.74752 km/h

Checked against: Exact-fraction computation from the legal unit definitions

Questions

How many kilometers per hour is one mile per hour?

1 mph is about 1.609344 km/h. mile per hour: 1 mph = 0.44704 m/s. These values are exact.

How do I convert miles per hour to kilometers per hour?

Multiply by 1.609344: 60 mph × 1.609344 ≈ 96.56064 km/h. To convert back, divide by the same factor. The factor shown may be rounded.

How can I estimate miles per hour in kilometers per hour without a calculator?

Multiply by 1.6. This is 0.6% below the exact factor (about 1.609344), so 60 mph comes out as 96 km/h instead of 96.5606 km/h.

About this calculator

km/h=mph×1.609344\text{km/h} = \text{mph} \times 1.609344

Sources

  1. NIST SP 811 (2008), Guide for the Use of the International System of Units, Appendix B
  2. NIST Handbook 44, Appendix C: General tables of units of measurement
  3. BIPM, The International System of Units (SI Brochure), 9th edition

Checked against references

This calculator includes 3 worked examples with independently sourced answers. They run in the test suite, and you can run them here too.

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